Various two component adhesive systems are known. These two component adhesives often contain, as the active component, polyester acrylate, resorcinol, phenol, epoxy, isocyanate acrylic, and the like. Conventionally the two components are precisely measured and mixed together prior to their use as an adhesive. If the measuring of the precise amount or if the mixing process is not carefully conducted, various desired adhesion properties may be substantially reduced. Additionally, with respect to many of these two component adhesive compositions, immediately after mixing, the components begin to react, build viscosity and eventually solidify to make the adhesive unusable. Thus, extended pot life is often a problem.
Various rapid setting two component adhesives have been proposed. For example, component A is applied to one substrate; component B is applied to the other substrate; and the substrates are contacted together to cause the components to rapidly react to form a bond between the substrates. See, for example, U.S. Pat. No. 3,870,675 to Kusayama et al. which proposes a component A comprising 40 to 80 parts by weight of at least one divinyl compound and 0.5 to 15 parts by weight acrylonitrile-butadiene-styrene polymer (ABR), acrylonitrile-butadiene rubber (NBR) or carboxylate rubber and component B comprising 0.01 to about 10 parts by weight of a thiourea compound, about 0.01 to about 10 parts by weight of .alpha.,.alpha.'-dipyridyl, 0.001 to 5 parts by weight of at least one of copper salts, cobalt salts, manganese salts, chromium salts and vanadium salts of organic and inorganic acids, and 75 to 100 parts by weight of an organic volatile solvent. The two components of the adhesive are separately applied to a surface of different articles and then the articles are combined together.
U.S. Pat. No. 4,431,757 to Okitsu et al. proposes a two component adhesive comprising solutions of components A and B. Component A is an aqueous solution of a high polymer having an amide bond or an imide bond within the molecule, or an aqueous dispersion obtained by adding a rubber latex and/or synthetic resin emulsion to the aqueous solution of the high polymer. Component B is an aqueous solution of a dialdehyde compound, or an aqueous solution or dispersion obtained by adding a crosslinking agent for crosslinking the high polymer of component A to the aqueous solution of the dialdehyde compound.
Most two component adhesives have to be applied using separate application means such as spray guns or a single application means having dual nozzles wherein the components react in the spray as the components are applied to a substrate. It would, however, be more desirable and is an object of the present invention to provide a two component adhesive suitable for applying using an application means which is adapted for dispensing single component adhesives.
It is another object of the present invention to provide a two component adhesive which can produce excellent green strength in a controlled yet rapid manner.
It is yet another object to provide a two component adhesive having an extended and usable pot life.